brake fluid recommendations

AP - Chris_B

Actually, the opposite is more likely true. The manufacturing process is the key to high-quality fluid. There are only a handful of chemical plants in the world equipped to make glycol ester-based brake fluid. Every label you see on the market comes from one of them. However, there are major differences in how the product is specified and what type of packaging process is used.

The better (more expensive) fluids on the market are packed in nitrogen, not air like some of the cheaper stuff. This means that the better fluids are actually "dry" when you crack the seal on the bottle. The cheaper fluids have already pulled whatever moisture they could out of the air they were packaged in, lower their boiling point efficacy. The cheap DOT4 stuff may have passed the SAE tests, but the product actually sitting on a store shelf may not have the exact same properties as what was tested in the lab.

Also, the more expensive fluids are typically more dense, meaning they have less dissolved air trapped in suspension. The more dense the fluid is (higher specific gravity), the better the brake pedal feels. Specifying a denser fluid adds production costs since it takes more times to make it. The cheaper fluids skip the extra steps.

But in all reality, if changing brake fluid every two years (like we are supposed to), the few extra bucks on a better fluid isn't really going to make much difference in overall maintenance costs per mile. Those tracking their cars will spend a lot more on fluid as they will replace it more often, but will also receive more benefit from the improved properties of the top shelf stuff (AP Racing PRF, Castrol SRF, Prospeed RS683, Motul RBF660 and a few others).

Chris